cds  2.3.1
cds::container::EllenBinTreeSet< cds::urcu::gc< RCU >, Key, T, Traits > Class Template Reference

Set based on Ellen's et al binary search tree (RCU specialization) More...

#include <cds/container/ellen_bintree_set_rcu.h>

Inheritance diagram for cds::container::EllenBinTreeSet< cds::urcu::gc< RCU >, Key, T, Traits >:
cds::intrusive::EllenBinTree< cds::urcu::gc< RCU >, Key, T, Traits >

Public Types

typedef cds::urcu::gc< RCU > gc
 RCU Garbage collector.
 
typedef Key key_type
 type of a key stored in internal nodes; key is a part of value_type
 
typedef T value_type
 type of value stored in the binary tree
 
typedef Traits traits
 Traits template parameter.
 
typedef implementation_defined key_comparator
 key compare functor based on Traits::compare and Traits::less
 
typedef base_class::item_counter item_counter
 Item counting policy.
 
typedef base_class::memory_model memory_model
 Memory ordering, see cds::opt::memory_model.
 
typedef base_class::stat stat
 internal statistics type
 
typedef base_class::rcu_check_deadlock rcu_check_deadlock
 Deadlock checking policy.
 
typedef traits::key_extractor key_extractor
 key extracting functor
 
typedef traits::back_off back_off
 Back-off strategy.
 
typedef traits::allocator allocator_type
 Allocator for leaf nodes.
 
typedef base_class::node_allocator node_allocator
 Internal node allocator.
 
typedef base_class::update_desc_allocator update_desc_allocator
 Update descriptor allocator.
 
typedef gc::scoped_lock rcu_lock
 RCU scoped lock.
 
using exempt_ptr = cds::urcu::exempt_ptr< gc, leaf_node, value_type, typename maker::intrusive_traits::disposer, cds::urcu::details::conventional_exempt_member_cast< leaf_node, value_type > >
 pointer to extracted node
 
- Public Types inherited from cds::intrusive::EllenBinTree< cds::urcu::gc< RCU >, Key, T, Traits >
typedef cds::urcu::gc< RCU > gc
 RCU Garbage collector.
 
typedef Key key_type
 type of a key stored in internal nodes; key is a part of value_type
 
typedef T value_type
 type of value stored in the binary tree
 
typedef Traits traits
 Traits template parameter.
 
typedef traits::hook hook
 hook type
 
typedef hook::node_type node_type
 node type
 
typedef traits::disposer disposer
 leaf node disposer
 
typedef traits::back_off back_off
 back-off strategy
 
using exempt_ptr = cds::urcu::exempt_ptr< gc, value_type, value_type, disposer, void >
 pointer to extracted node
 
typedef implementation_defined key_comparator
 key compare functor based on Traits::compare and Traits::less
 
typedef get_node_traits< value_type, node_type, hook >::type node_traits
 Node traits.
 
typedef traits::item_counter item_counter
 Item counting policy used.
 
typedef traits::memory_model memory_model
 Memory ordering. See cds::opt::memory_model option.
 
typedef traits::stat stat
 internal statistics type
 
typedef traits::rcu_check_deadlock rcu_check_deadlock
 Deadlock checking policy.
 
typedef traits::key_extractor key_extractor
 key extracting functor
 
typedef traits::node_allocator node_allocator
 Internal node allocator.
 
typedef traits::update_desc_allocator update_desc_allocator
 Update descriptor allocator.
 
typedef gc::scoped_lock rcu_lock
 RCU scoped lock.
 

Public Member Functions

 EllenBinTreeSet ()
 Default constructor.
 
 ~EllenBinTreeSet ()
 Clears the set.
 
template<typename Q >
bool insert (Q const &val)
 Inserts new node. More...
 
template<typename Q , typename Func >
bool insert (Q const &val, Func f)
 Inserts new node. More...
 
template<typename Q , typename Func >
std::pair< bool, bool > update (Q const &val, Func func, bool bAllowInsert=true)
 Updates the node. More...
 
template<typename... Args>
bool emplace (Args &&... args)
 Inserts data of type value_type created in-place from args. More...
 
template<typename Q >
bool erase (Q const &key)
 Delete key from the set. More...
 
template<typename Q , typename Less >
bool erase_with (Q const &key, Less pred)
 Deletes the item from the set using pred predicate for searching. More...
 
template<typename Q , typename Func >
bool erase (Q const &key, Func f)
 Delete key from the set. More...
 
template<typename Q , typename Less , typename Func >
bool erase_with (Q const &key, Less pred, Func f)
 Deletes the item from the set using pred predicate for searching. More...
 
exempt_ptr extract_min ()
 Extracts an item with minimal key from the set. More...
 
exempt_ptr extract_max ()
 Extracts an item with maximal key from the set. More...
 
template<typename Q >
exempt_ptr extract (Q const &key)
 Extracts an item from the set. More...
 
template<typename Q , typename Less >
exempt_ptr extract_with (Q const &key, Less pred)
 Extracts an item from the set using pred for searching. More...
 
template<typename Q , typename Func >
bool find (Q &key, Func f) const
 Find the key key. More...
 
template<typename Q , typename Less , typename Func >
bool find_with (Q &key, Less pred, Func f) const
 Finds the key key using pred predicate for searching. More...
 
template<typename Q >
bool contains (Q const &key) const
 Checks whether the set contains key. More...
 
template<typename Q , typename Less >
bool contains (Q const &key, Less pred) const
 Checks whether the set contains key using pred predicate for searching. More...
 
template<typename Q >
value_typeget (Q const &key) const
 Finds key and return the item found. More...
 
template<typename Q , typename Less >
value_typeget_with (Q const &key, Less pred) const
 Finds key with pred predicate and return the item found. More...
 
void clear ()
 Clears the set (non-atomic) More...
 
bool empty () const
 Checks if the set is empty.
 
size_t size () const
 Returns item count in the set. More...
 
stat const & statistics () const
 Returns const reference to internal statistics.
 
bool check_consistency () const
 Checks internal consistency (not atomic, not thread-safe) More...
 
- Public Member Functions inherited from cds::intrusive::EllenBinTree< cds::urcu::gc< RCU >, Key, T, Traits >
 EllenBinTree ()
 Default constructor.
 
 ~EllenBinTree ()
 Clears the tree.
 
bool insert (value_type &val)
 Inserts new node. More...
 
template<typename Func >
bool insert (value_type &val, Func f)
 Inserts new node. More...
 
template<typename Func >
std::pair< bool, bool > update (value_type &val, Func func, bool bAllowInsert=true)
 Updates the node. More...
 
bool unlink (value_type &val)
 Unlinks the item val from the tree. More...
 
template<typename Q >
bool erase (const Q &key)
 Deletes the item from the tree. More...
 
template<typename Q , typename Less >
bool erase_with (const Q &key, Less pred)
 Delete the item from the tree with comparing functor pred. More...
 
template<typename Q , typename Func >
bool erase (Q const &key, Func f)
 Deletes the item from the tree. More...
 
template<typename Q , typename Less , typename Func >
bool erase_with (Q const &key, Less pred, Func f)
 Delete the item from the tree with comparing functor pred. More...
 
exempt_ptr extract_min ()
 Extracts an item with minimal key from the tree. More...
 
exempt_ptr extract_max ()
 Extracts an item with maximal key from the tree. More...
 
template<typename Q >
exempt_ptr extract (Q const &key)
 Extracts an item from the tree. More...
 
template<typename Q , typename Less >
exempt_ptr extract_with (Q const &key, Less pred)
 Extracts an item from the set using pred for searching. More...
 
template<typename Q >
bool contains (Q const &key) const
 Checks whether the set contains key. More...
 
template<typename Q , typename Less >
bool contains (Q const &key, Less pred) const
 Checks whether the set contains key using pred predicate for searching. More...
 
template<typename Q , typename Func >
bool find (Q &key, Func f) const
 Finds the key key. More...
 
template<typename Q , typename Less , typename Func >
bool find_with (Q &key, Less pred, Func f) const
 Finds the key key with comparing functor pred. More...
 
template<typename Q >
value_typeget (Q const &key) const
 Finds key and return the item found. More...
 
template<typename Q , typename Less >
value_typeget_with (Q const &key, Less pred) const
 Finds key with pred predicate and return the item found. More...
 
bool empty () const
 Checks if the tree is empty.
 
void clear ()
 Clears the tree (thread safe, not atomic) More...
 
void unsafe_clear ()
 Clears the tree (not thread safe) More...
 
size_t size () const
 Returns item count in the tree. More...
 
stat const & statistics () const
 Returns const reference to internal statistics.
 
bool check_consistency () const
 Checks internal consistency (not atomic, not thread-safe) More...
 

Static Public Attributes

static constexpr const bool c_bExtractLockExternal = base_class::c_bExtractLockExternal
 Group of extract_xxx functions do not require external locking.
 
- Static Public Attributes inherited from cds::intrusive::EllenBinTree< cds::urcu::gc< RCU >, Key, T, Traits >
static constexpr const bool c_bExtractLockExternal = false
 Group of extract_xxx functions do not require external locking.
 

Additional Inherited Members

- Protected Attributes inherited from cds::intrusive::EllenBinTree< cds::urcu::gc< RCU >, Key, T, Traits >
item_counter m_ItemCounter
 item counter
 
stat m_Stat
 internal statistics
 

Detailed Description

template<class RCU, typename Key, typename T, class Traits = ellen_bintree::traits>
class cds::container::EllenBinTreeSet< cds::urcu::gc< RCU >, Key, T, Traits >

Set based on Ellen's et al binary search tree (RCU specialization)

Source:

  • [2010] F.Ellen, P.Fatourou, E.Ruppert, F.van Breugel "Non-blocking Binary Search Tree"

EllenBinTreeSet is an unbalanced leaf-oriented binary search tree that implements the set abstract data type. Nodes maintains child pointers but not parent pointers. Every internal node has exactly two children, and all data of type T currently in the tree are stored in the leaves. Internal nodes of the tree are used to direct find operation along the path to the correct leaf. The keys (of Key type) stored in internal nodes may or may not be in the set. Key type is a subset of T type. There should be exactly defined a key extracting functor for converting object of type T to object of type Key.

Due to extract_min and extract_max member functions the EllenBinTreeSet can act as a priority queue. In this case you should provide unique compound key, for example, the priority value plus some uniformly distributed random value.

Warning
Recall the tree is unbalanced. The complexity of operations is O(log N) for uniformly distributed random keys, but in the worst case the complexity is O(N).
Note
In the current implementation we do not use helping technique described in original paper. So, the current implementation is near to fine-grained lock-based tree. Helping will be implemented in future release

Template arguments :

Note
Before including <cds/container/ellen_bintree_set_rcu.h> you should include appropriate RCU header file, see RCU type for list of existing RCU class and corresponding header files.

Predicate requirements

opt::less, opt::compare and other predicates using with member fuctions should accept at least parameters of type T and Key in any combination. For example, for Foo struct with std::string key field the appropiate less functor is:

struct Foo
{
std::string m_strKey;
...
};
struct less {
bool operator()( Foo const& v1, Foo const& v2 ) const
{ return v1.m_strKey < v2.m_strKey ; }
bool operator()( Foo const& v, std::string const& s ) const
{ return v.m_strKey < s ; }
bool operator()( std::string const& s, Foo const& v ) const
{ return s < v.m_strKey ; }
// Support comparing std::string and char const *
bool operator()( std::string const& s, char const * p ) const
{ return s.compare(p) < 0 ; }
bool operator()( Foo const& v, char const * p ) const
{ return v.m_strKey.compare(p) < 0 ; }
bool operator()( char const * p, std::string const& s ) const
{ return s.compare(p) > 0; }
bool operator()( char const * p, Foo const& v ) const
{ return v.m_strKey.compare(p) > 0; }
};

Member Function Documentation

◆ check_consistency()

template<class RCU , typename Key , typename T , class Traits = ellen_bintree::traits>
bool cds::container::EllenBinTreeSet< cds::urcu::gc< RCU >, Key, T, Traits >::check_consistency ( ) const
inline

Checks internal consistency (not atomic, not thread-safe)

The debugging function to check internal consistency of the tree.

◆ clear()

template<class RCU , typename Key , typename T , class Traits = ellen_bintree::traits>
void cds::container::EllenBinTreeSet< cds::urcu::gc< RCU >, Key, T, Traits >::clear ( )
inline

Clears the set (non-atomic)

The function unlink all items from the tree. The function is not atomic, thus, in multi-threaded environment with parallel insertions this sequence

set.clear();
assert( set.empty());

the assertion could be raised.

For each leaf the disposer will be called after unlinking.

RCU synchronize method can be called. RCU should not be locked.

◆ contains() [1/2]

template<class RCU , typename Key , typename T , class Traits = ellen_bintree::traits>
template<typename Q >
bool cds::container::EllenBinTreeSet< cds::urcu::gc< RCU >, Key, T, Traits >::contains ( Q const &  key) const
inline

Checks whether the set contains key.

The function searches the item with key equal to key and returns true if it is found, and false otherwise.

The function applies RCU lock internally.

◆ contains() [2/2]

template<class RCU , typename Key , typename T , class Traits = ellen_bintree::traits>
template<typename Q , typename Less >
bool cds::container::EllenBinTreeSet< cds::urcu::gc< RCU >, Key, T, Traits >::contains ( Q const &  key,
Less  pred 
) const
inline

Checks whether the set contains key using pred predicate for searching.

The function is similar to contains( key ) but pred is used for key comparing. Less functor has the interface like std::less and should meet Predicate requirements. Less must imply the same element order as the comparator used for building the set. pred should accept arguments of type Q, key_type, value_type in any combination.

◆ emplace()

template<class RCU , typename Key , typename T , class Traits = ellen_bintree::traits>
template<typename... Args>
bool cds::container::EllenBinTreeSet< cds::urcu::gc< RCU >, Key, T, Traits >::emplace ( Args &&...  args)
inline

Inserts data of type value_type created in-place from args.

Returns true if inserting successful, false otherwise.

RCU synchronize method can be called. RCU should not be locked.

◆ erase() [1/2]

template<class RCU , typename Key , typename T , class Traits = ellen_bintree::traits>
template<typename Q >
bool cds::container::EllenBinTreeSet< cds::urcu::gc< RCU >, Key, T, Traits >::erase ( Q const &  key)
inline

Delete key from the set.

The item comparator should be able to compare the type value_type and the type Q.

RCU synchronize method can be called. RCU should not be locked.

Return true if key is found and deleted, false otherwise

◆ erase() [2/2]

template<class RCU , typename Key , typename T , class Traits = ellen_bintree::traits>
template<typename Q , typename Func >
bool cds::container::EllenBinTreeSet< cds::urcu::gc< RCU >, Key, T, Traits >::erase ( Q const &  key,
Func  f 
)
inline

Delete key from the set.

The function searches an item with key key, calls f functor and deletes the item. If key is not found, the functor is not called.

The functor Func interface:

struct extractor {
void operator()(value_type const& val);
};

Since the key of MichaelHashSet's value_type is not explicitly specified, template parameter Q defines the key type searching in the list. The list item comparator should be able to compare the type T of list item and the type Q.

RCU synchronize method can be called. RCU should not be locked.

Return true if key is found and deleted, false otherwise

See also: erase

◆ erase_with() [1/2]

template<class RCU , typename Key , typename T , class Traits = ellen_bintree::traits>
template<typename Q , typename Less >
bool cds::container::EllenBinTreeSet< cds::urcu::gc< RCU >, Key, T, Traits >::erase_with ( Q const &  key,
Less  pred 
)
inline

Deletes the item from the set using pred predicate for searching.

The function is an analog of erase(Q const&) but pred is used for key comparing. Less functor has the interface like std::less. Less must imply the same element order as the comparator used for building the set.

◆ erase_with() [2/2]

template<class RCU , typename Key , typename T , class Traits = ellen_bintree::traits>
template<typename Q , typename Less , typename Func >
bool cds::container::EllenBinTreeSet< cds::urcu::gc< RCU >, Key, T, Traits >::erase_with ( Q const &  key,
Less  pred,
Func  f 
)
inline

Deletes the item from the set using pred predicate for searching.

The function is an analog of erase(Q const&, Func) but pred is used for key comparing. Less functor has the interface like std::less. Less must imply the same element order as the comparator used for building the set.

◆ extract()

template<class RCU , typename Key , typename T , class Traits = ellen_bintree::traits>
template<typename Q >
exempt_ptr cds::container::EllenBinTreeSet< cds::urcu::gc< RCU >, Key, T, Traits >::extract ( Q const &  key)
inline

Extracts an item from the set.

The function searches an item with key equal to key in the tree, unlinks it, and returns exempt_ptr pointer to an item found. If key is not found the function returns an empty exempt_ptr.

RCU synchronize method can be called. RCU should NOT be locked. The function does not destroy the item found. The dealloctor will be implicitly invoked when the returned object is destroyed or when its release() member function is called.

◆ extract_max()

template<class RCU , typename Key , typename T , class Traits = ellen_bintree::traits>
exempt_ptr cds::container::EllenBinTreeSet< cds::urcu::gc< RCU >, Key, T, Traits >::extract_max ( )
inline

Extracts an item with maximal key from the set.

Returns exempt_ptr pointer to the rightmost item. If the set is empty, returns empty exempt_ptr.

Note
Due the concurrent nature of the set, the function extracts nearly maximal key. It means that the function gets rightmost leaf of the tree and tries to unlink it. During unlinking, a concurrent thread may insert an item with key great than leftmost item's key. So, the function returns the item with maximum key at the moment of tree traversing.

RCU synchronize method can be called. RCU should NOT be locked. The function does not free the item. The deallocator will be implicitly invoked when the returned object is destroyed or when its release() member function is called.

◆ extract_min()

template<class RCU , typename Key , typename T , class Traits = ellen_bintree::traits>
exempt_ptr cds::container::EllenBinTreeSet< cds::urcu::gc< RCU >, Key, T, Traits >::extract_min ( )
inline

Extracts an item with minimal key from the set.

Returns exempt_ptr pointer to the leftmost item. If the set is empty, returns empty exempt_ptr.

Note
Due the concurrent nature of the set, the function extracts nearly minimum key. It means that the function gets leftmost leaf of the tree and tries to unlink it. During unlinking, a concurrent thread may insert an item with key less than leftmost item's key. So, the function returns the item with minimum key at the moment of tree traversing.

RCU synchronize method can be called. RCU should NOT be locked. The function does not free the item. The deallocator will be implicitly invoked when the returned object is destroyed or when its release() member function is called.

◆ extract_with()

template<class RCU , typename Key , typename T , class Traits = ellen_bintree::traits>
template<typename Q , typename Less >
exempt_ptr cds::container::EllenBinTreeSet< cds::urcu::gc< RCU >, Key, T, Traits >::extract_with ( Q const &  key,
Less  pred 
)
inline

Extracts an item from the set using pred for searching.

The function is an analog of extract(Q const&) but pred is used for key compare. Less has the interface like std::less and should meet predicate requirements. pred must imply the same element order as the comparator used for building the set.

◆ find()

template<class RCU , typename Key , typename T , class Traits = ellen_bintree::traits>
template<typename Q , typename Func >
bool cds::container::EllenBinTreeSet< cds::urcu::gc< RCU >, Key, T, Traits >::find ( Q &  key,
Func  f 
) const
inline

Find the key key.

The function searches the item with key equal to key and calls the functor f for item found. The interface of Func functor is:

struct functor {
void operator()( value_type& item, Q& key );
};

where item is the item found, key is the find function argument.

The functor may change non-key fields of item. Note that the functor is only guarantee that item cannot be disposed during functor is executing. The functor does not serialize simultaneous access to the set's item. If such access is possible you must provide your own synchronization schema on item level to exclude unsafe item modifications.

The key argument is non-const since it can be used as f functor destination i.e., the functor can modify both arguments.

Note the hash functor specified for class Traits template parameter should accept a parameter of type Q that may be not the same as value_type.

The function applies RCU lock internally.

The function returns true if key is found, false otherwise.

◆ find_with()

template<class RCU , typename Key , typename T , class Traits = ellen_bintree::traits>
template<typename Q , typename Less , typename Func >
bool cds::container::EllenBinTreeSet< cds::urcu::gc< RCU >, Key, T, Traits >::find_with ( Q &  key,
Less  pred,
Func  f 
) const
inline

Finds the key key using pred predicate for searching.

The function is an analog of find(Q&, Func) but pred is used for key comparing. Less functor has the interface like std::less. Less must imply the same element order as the comparator used for building the set.

◆ get()

template<class RCU , typename Key , typename T , class Traits = ellen_bintree::traits>
template<typename Q >
value_type* cds::container::EllenBinTreeSet< cds::urcu::gc< RCU >, Key, T, Traits >::get ( Q const &  key) const
inline

Finds key and return the item found.

The function searches the item with key equal to key and returns the pointer to item found. If key is not found it returns nullptr.

RCU should be locked before call the function. Returned pointer is valid while RCU is locked.

◆ get_with()

template<class RCU , typename Key , typename T , class Traits = ellen_bintree::traits>
template<typename Q , typename Less >
value_type* cds::container::EllenBinTreeSet< cds::urcu::gc< RCU >, Key, T, Traits >::get_with ( Q const &  key,
Less  pred 
) const
inline

Finds key with pred predicate and return the item found.

The function is an analog of get(Q const&) but pred is used for comparing the keys.

Less functor has the semantics like std::less but should take arguments of type value_type and Q in any order. pred must imply the same element order as the comparator used for building the set.

◆ insert() [1/2]

template<class RCU , typename Key , typename T , class Traits = ellen_bintree::traits>
template<typename Q >
bool cds::container::EllenBinTreeSet< cds::urcu::gc< RCU >, Key, T, Traits >::insert ( Q const &  val)
inline

Inserts new node.

The function creates a node with copy of val value and then inserts the node created into the set.

The type Q should contain at least the complete key for the node. The object of value_type should be constructible from a value of type Q. In trivial case, Q is equal to value_type.

RCU synchronize() method can be called. RCU should not be locked.

Returns true if val is inserted into the set, false otherwise.

◆ insert() [2/2]

template<class RCU , typename Key , typename T , class Traits = ellen_bintree::traits>
template<typename Q , typename Func >
bool cds::container::EllenBinTreeSet< cds::urcu::gc< RCU >, Key, T, Traits >::insert ( Q const &  val,
Func  f 
)
inline

Inserts new node.

The function allows to split creating of new item into two part:

  • create item with key only
  • insert new item into the set
  • if inserting is success, calls f functor to initialize value-fields of val.

The functor signature is:

void func( value_type& val );

where val is the item inserted. User-defined functor f should guarantee that during changing val no any other changes could be made on this set's item by concurrent threads. The user-defined functor is called only if the inserting is success.

RCU synchronize() can be called. RCU should not be locked.

◆ size()

template<class RCU , typename Key , typename T , class Traits = ellen_bintree::traits>
size_t cds::container::EllenBinTreeSet< cds::urcu::gc< RCU >, Key, T, Traits >::size ( ) const
inline

Returns item count in the set.

Only leaf nodes containing user data are counted.

The value returned depends on item counter type provided by Traits template parameter. If it is atomicity::empty_item_counter size() always returns 0. Therefore, the function is not suitable for checking the tree emptiness, use empty() member function for this purpose.

◆ update()

template<class RCU , typename Key , typename T , class Traits = ellen_bintree::traits>
template<typename Q , typename Func >
std::pair<bool, bool> cds::container::EllenBinTreeSet< cds::urcu::gc< RCU >, Key, T, Traits >::update ( Q const &  val,
Func  func,
bool  bAllowInsert = true 
)
inline

Updates the node.

The operation performs inserting or changing data with lock-free manner.

If the item val is not found in the set, then val is inserted into the set iff bAllowInsert is true. Otherwise, the functor func is called with item found. The functor func signature is:

void func( bool bNew, value_type& item, value_type& val );

with arguments:

  • bNew - true if the item has been inserted, false otherwise
  • item - item of the set
  • val - argument val passed into the update() function

The functor can change non-key fields of the item; however, func must guarantee that during changing no any other modifications could be made on this item by concurrent threads.

RCU synchronize method can be called. RCU should not be locked.

Returns std::pair<bool, bool> where first is true if operation is successful, i.e. the node has been inserted or updated, second is true if new item has been added or false if the item with key already exists.

Warning
See insert item troubleshooting

The documentation for this class was generated from the following file:

cds 2.3.1 Developed by Maxim Khizhinsky aka khizmax 2007 - 2017
Autogenerated Fri Sep 1 2017 08:46:58 by Doxygen 1.8.13